R-tech OK for under slab?

[ranchero7]

I'm getting ready to put my garage slab (22*30) in a few weeks. I've read many posts here and most seem to use blue or pink XPS. I've received mixed information about whether R-tech, an EPS product available at Lowe's, is acceptable.

2"x4'x8' Blue Dow boards are $35 in my area
R-tech is 25 at Lowes.

I'm doing radiant and slab will be about 5" thick.

Thanks!
Steve

 

[HoosierBuddy]

IIWY I'd check with the manufacturer and make sure the product is rated for underslab use. When I did mine in 2006, high density polystyrene was kind of the "gold standard" for underslab use. They didn't sell that at my local lowes. They sold 2" polystyrene from Dow, but it wasn't the type for underslab use. I was able to get that through the concrete company along with the reinforcing wire (actually a grid for my pex to tie to for the radiant heat).

Phil

 

[ranchero7]

HoosierBuddy - thanks. The R-tech stuff is ok under residential slabs according to the website. But...went down to Lowe's (100 mi away) and found out that what they advertised as R-tech was Perma-R, which is not rated for under slabs. The manager threw me a bone and sold me 2"*2'*8' Blue Dow XPS for $15/sheet. A little more than I was planning on, but cheaper than up here by $4/sheet.
Steve